California wildfires prompt ‘Spare the Air’ days...

1of 18A chimney remains standing at a house destroyed in the Ranch Fire in Spring Valley near Clearlake Oaks, northern California, on August 7, 2018. Smoke from Northern California wildfires drifting into the Bay Area has prompted air quality officials to declare Spare the Air Days for Wednesday and Thursday and caution people sensitive to smoke to stay indoors when possible.Photo: JOSH EDELSON / AFP/Getty Images

2of 18Firefighters monitor a back fire as they battle the Medocino Complex fire on August 7, 2018 near Lodoga, California. The Mendocino Complex Fire, which is made up of the River Fire and Ranch Fire, has surpassed the Thomas Fire to become the largest wildfire in California state history with over 280,000 acres charred and at least 75 homes destroyed.Photo: Justin Sullivan / Getty Images

3of 18This photo shows burnt out cars after the Ranch Fire, part of the Mendocino Complex Fire, hit Spring Valley near Clearlake Oaks, northern California, on August 7, 2018. Tens of thousands of firefighters battled relentless flames ripping across California on August 7, as the death toll from a series of infernos that erupted last month hit 11. The raging Mendocino Complex fire comprising twin blazes in the western state's north has now ravaged more than 290,000 acres (117,359 hectares) -- approximately the size of sprawling Los Angeles -- in less than two weeks, becoming California's largest wildfire since record-keeping began a century ago.Photo: JOSH EDELSON / AFP/Getty Images

4of 18A Cal Fire firefighter monitors a back fire while battling the Medocino Complex fire on August 7, 2018 near Lodoga, California. The Mendocino Complex Fire, which is made up of the River Fire and Ranch Fire, has surpassed the Thomas Fire to become the largest wildfire in California state history with over 280,000 acres charred and at least 75 homes destroyed.Photo: Justin Sullivan / Getty Images

5of 18Here are the dumbest, most careless human causes for wildfires that we could find.Photo: Marcio Jose Sanchez, Associated Press

6of 1813. Target shooting. Generally it's not the bullets themselves, but rather the sparks from shots off metal targets or stone that start fires.
Example: A 2013 fire on Mt. Diablo burned that burned 3,111 acres was blamed on a target shooter firing a rifle.Photo: Berggren, Hans/Getty Images/Johner RF

7of 1812. Ash clowns: While fewer wildfires are started by cigarettes today as compared to past decades, some people still feel entitled to recklessly toss their butts (and the matches they lit them with) wherever they please.
Example: The 2017 York Fire in Monterey County was started by a cigarette. It burned several homes and 31 acres near a school.Photo: Denise Brodling / EyeEm/Getty Images/EyeEm

8of 1811. Setting off fireworks on the Fourth. About half the fires occurring nationally on July 4th — more than 7,000 — are caused by fireworks, according to CalFire. Is it time to ban personal pyrotechnics?
Examples: A 115-acre wildfire in White City, Ore., was sparked by a teenager two days after the Fourth of July this year. Also, a small wildfire on National Forest lands in Payson, Ariz., in April was blamed on the illegal use of fireworks.Photo: Dima Viunnyk/Getty Images

9of 1810. Chains dragging from trailers. How hard is it to secure a loose chain?
Examples: Wildfires started from loose trailer chains hitting road pavement and showering roadsides with sparks have been reported in many states, including Utah, Florida, Arizona and California.Photo: papa1266/Getty Images/iStockphoto

10of 189. You're driving on a flat tire: Drivers are sometimes unaware that a tire has gone flat, and when the rubber peels off, the rim scatters sparks, which in turn start fires. Tires should be inspected regularly for tread wear and proper inflation.Examples: The 2016 Willow Valley Fire in San Andreas, Calif., was caused by a woman on pain meds driving on exposed wheel rims. The cause of the ongoing Carr Fire near Redding, Calif., was listed as "mechanical failure of vehicle," which may have been related to a trailer causing sparks.Photo: Getty Images

11of 188. Hot tub amateur hour: Someone thought they would save some money by installing the wiring themselves instead of getting an electrician to do the job to code. Bad idea.
Example: An improperly installed hot tub power unit was blamed for the 2015 Valley Fire, which burned 76,067 acres in Lake, Napa and Sonoma counties. Four people died and nearly 2,000 structures were lost.Photo: Oliver Best / EyeEm/Getty Images/EyeEm

12of 187. Failing to maintain areas around power lines. Who knew that power lines knocked down by the wind could ignite brush that should have been cleared, but wasn't? PG&E, that's who, according to fire investigators.
Examples: Cal Fire found PG&E in violation of state code in eight Northern California wildfires in October: Norrbom, Patrick, Pythian, Adobe and Pocket fires that burned in Sonoma and Napa counties; the Atlas Fire in Napa County; the Sulphur Fire in Lake County; and the Blue Fire in Humboldt County. The verdict is still out on whether this was the cause of the Tubbs Fire, the most destructive fire in state history.Photo: BackyardProduction/Getty Images/iStockphoto

13of 186. Grinding or cutting metal in an area with combustable vegetation. What, the fountain of sparks didn't raise a flag?!Example: The 2007 Zaca Fire, which burned 240,207 acres in Santa Barbara County, was traced to equipment grinding a metal pipe on a ranch.Photo: Koldunov/Getty Images/iStockphoto

14of 185. Illegal and/or neglected campfires. Smokey the Bear has been warning people to be careful with campfires for decades, but his admonition often goes unheeded or is openly flouted.
Examples: The devastating 2015 Rim Fire, which charred 257,314 acres near Yosemite and destroyed 112 structures, was caused by a bowhunter's illegal campfire. Also: An abandoned illegal campfire took off about 2 miles east of Highway 1 along Soberanes Creek in an isolated area of Garrapata State Park, spawning the 2016 Soberanes Fire, which burned 132,127 acres in Monterey County. One person died.Photo: LPinchuk/Getty Images/iStockphoto

15of 184. Playing with smoke bombs in the wilderness: An Oregon youth chose to lob one in Mount Hood National Forest, starting the massive Eagle Creek Fire. A judge later orders him to pay restitution of $36.6 million.
Example: The 2017 Eagle Creek Fire in Mount Hood National Forest burned 48,000 acres and cost $40 million to fight.Photo: Waldemar Blazej Nowak / EyeEm/Getty Images/EyeEm

16of 183. Mowing your dry grass lawn on a scorching day when everyone is warning you not to.Example: The 2004 Bear Fire destroyed 110 structures, including 86 homes, thanks to a man named Matt Rupp. Prosecutors said Rupp ignored warnings not to mow — from neighbors and public-service spots on TV — and told one passer-by, "Go to hell." A blade hit a rock, creating a spark and the spark became the Bear Fire. Rupp was sentenced to four years in prison and served two years before being paroled.Photo: Zsolt Ãveges / EyeEm/Getty Images/EyeEm

17of 182. Intentionally starting a fire to make money as a firefighter.Example: Part-time Arizona firefighter Leonard Gregg started the 2002 Rodeo Fire, which burned 469,000 acres and destroyed 423 homes, in order to gin up work. Some 32,000 people were evacuated after the Rodeo Fire merged with the Chediski Fire, creating the largest blaze in Arizona history at the time. Gregg was ordered to pay $28 million.Photo: Rolfo Brenner / EyeEm/Getty Images/EyeEm

18of 181. Starting a fire and then filming yourself in front of the burning forest so you can get attention on Facebook and one day become a weatherman.Example: That's what police say aspiring meteorologist Johnny Mullin, 21, did. Mullin was arrested and charged with second-degree arson for setting a 2016 blaze in eastern Kentucky. In Mullin's video posted to Facebook, he warns viewers to "be extremely careful if you're out there."
Photo: Facebook video screen shot

Smoke from Northern California wildfires drifting into the Bay Area has prompted air quality officials to declare Spare the Air Days for Wednesday and Thursday and caution people sensitive to smoke to stay indoors when possible.

Air quality is particularly bad in the East Bay valleys, where the smell of smoke is strong. Most of the smoke is coming into the Bay Area from the massive Mendocino Complex fires in Lake, Mendocino and Colusa counties.

Officials with the Bay Area Air Quality Management District say the poor air quality is caused by a combination of wildfire smoke and smog.

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Cristina Rendon has the report

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When the smell of smoke is in the air, air quality officials advise, Bay Area residents should stay inside, with windows and doors closed, and use air conditioners and car ventilation systems to recirculate air and prevent outside air from coming inside the vehicle.

Smoke can irritate eyes and airways to cause coughing, a scratchy throat and irritated sinuses. It can also cause wheezing among those who suffer from asthma, emphysema or chronic obstructive pulmonary disease, officials said.

Michael Cabanatuan has covered all things transportation for the San Francisco Chronicle — from BART strikes, acrobatic bridge construction and dark dirty tunnel excavations to the surging ridership on public transportation and the increasing conflict as cars, bikes and pedestrians struggle to coexist on the streets. He’s ridden high-speed trains in Japan, walked in BART’s Transbay Tube and driven to King City at 55 mph to test fuel efficiency.

He joined The Chronicle as a suburban reporter and deputy bureau chief in Contra Costa County, and has also covered the general assignment beat. In addition to transportation, Michael covers a variety of Bay Area news, including breaking news events. He’s been tear-gassed covering demonstrations in Oakland and exposed to nude protesters in the Castro District. Michael is also a regular contributor to the City Insider column and blog.